54 Second Report on Economic Zoology . 
Fumigation with Hydrocyanic Acid Gas. 
Mr. J. A. Richmonds, of Woodlands, Lustleigh, South Devon, 
wrote asking for information re fumigation for Mealy Bug. The 
following reply was sent — 
“With regard to fumigation with hydrocyanic acid gas, I can 
confidently say that the eggs of Mealy Bug are not all killed. In 
my opinion, two fumigations are necessary at ten days’ interval. 
“ The quantities to use are : 5 ozs. sulphuric acid, 3 ozs. cyanide 
of potassium, 8 ozs. water, to every 1000 cubic feet. 
“ If the house is more than 10,000 cubic feet another jar will be 
required, and for every additional 10,000 cubic feet. 
“ The water should be put in a jar and then the acid added to it, 
the cyanide in small lumps wrapped in blotting-paper ; the cyanide 
is then dropped into the jar with the acid and water and allowed to 
stand for one hour. 
“ This must be done quickly, as the fumes are poisonous to man, 
and all, or nearly all, animal life. 
“ The cyanide should be dropped into the acid and water from 
outside the house. 
“ Temperature of house never more than 60° Fahr. 
“ Do not fumigate in strong light. 
“ Do not fumigate vines in bloom. 
“Fumigate (i) before the vines bloom ; and (ii) after the crop has 
been gathered. 
“ The house must be well ventilated for at least one hour after 
fumigation before anyone is allowed to enter.” 
Field Mice damaging Apple Trees. 
Quite a new attack upon fruit trees has been recorded by Mr. 
Hammond, of Canterbury. On the 2nd of April Mr. Hammond 
wrote that “ a few days ago I was looking over some apple trees in my 
garden, when I came upon one with the spurs right up to the very 
top of the tree gnawed all around by some animal. I have never seen 
anything like it before, but I think it must have been done either by 
a squirrel or field mice. The material was examined, and the 
following reply sent : — 
“ I think the damaged twigs of apple you send have been eaten 
by field mice, not by squirrels ; the marks of the teeth do not seem 
large enough for the latter. I have never seen any such damage in 
